can a step parent adoption be reversed

my attorney and i are all ready getting preparing for the hearing, we covered this subject this week on back child support and his answer was when the rights of the parent are terminated it is as if that parent was never the parent and she cant seek chjild support for any period...concept being if i am responsible for CS than i should also have my parental rights which is something i was never allowed to have because i never knew there was a child...the only way to get CS from any period is to reverse the adoption and give me parental rights.